/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation.
 * Copyright(c) 2016 6WIND S.A.
 */

#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdarg.h>
#include <unistd.h>
#include <inttypes.h>
#include <errno.h>
#include <sys/queue.h>

#include <rte_common.h>
#include <rte_log.h>
#include <rte_debug.h>
#include <rte_memory.h>
#include <rte_memzone.h>
#include <rte_malloc.h>
#include <rte_atomic.h>
#include <rte_launch.h>
#include <rte_eal.h>
#include <rte_eal_memconfig.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_branch_prediction.h>
#include <rte_errno.h>
#include <rte_string_fns.h>
#include <rte_spinlock.h>
#include <rte_tailq.h>
#include <rte_eal_paging.h>

#include "rte_mempool.h"
#include "rte_mempool_trace.h"

TAILQ_HEAD(rte_mempool_list, rte_tailq_entry
);

//创建尾队列的配置信息
static struct rte_tailq_elem rte_mempool_tailq = {
        .name = "RTE_MEMPOOL",
};
//向共享内存中注册内存池的尾队列
EAL_REGISTER_TAILQ(rte_mempool_tailq)

#define CACHE_FLUSHTHRESH_MULTIPLIER 1.5
#define CALC_CACHE_FLUSHTHRESH(c)    \
    ((typeof(c))((c) * CACHE_FLUSHTHRESH_MULTIPLIER))

#if defined(RTE_ARCH_X86)
/*
 * return the greatest common divisor between a and b (fast algorithm)
 *
 */
static unsigned get_gcd(unsigned a, unsigned b)
{
    unsigned c;

    if (0 == a)
        return b;
    if (0 == b)
        return a;

    if (a < b) {
        c = a;
        a = b;
        b = c;
    }

    while (b != 0) {
        c = a % b;
        a = b;
        b = c;
    }

    return a;
}

/*
 * Depending on memory configuration on x86 arch, objects addresses are spread
 * between channels and ranks in RAM: the pool allocator will add
 * padding between objects. This function return the new size of the
 * object.
 */
static unsigned int
arch_mem_object_align(unsigned int obj_size)
{
    unsigned nrank, nchan;
    unsigned new_obj_size;

    /* get number of channels */
    nchan = rte_memory_get_nchannel();
    if (nchan == 0)
        nchan = 4;

    nrank = rte_memory_get_nrank();
    if (nrank == 0)
        nrank = 1;

    /* process new object size */
    new_obj_size = (obj_size + RTE_MEMPOOL_ALIGN_MASK) / RTE_MEMPOOL_ALIGN;
    while (get_gcd(new_obj_size, nrank * nchan) != 1)
        new_obj_size++;
    return new_obj_size * RTE_MEMPOOL_ALIGN;
}
#else

static unsigned int
arch_mem_object_align(unsigned int obj_size) {
    return obj_size;
}

#endif

struct pagesz_walk_arg {
    int socket_id;
    size_t min;
};

static int
find_min_pagesz(const struct rte_memseg_list *msl, void *arg) {
    struct pagesz_walk_arg *wa = arg;
    bool valid;

    /*
     * we need to only look at page sizes available for a particular socket
     * ID.  so, we either need an exact match on socket ID (can match both
     * native and external memory), or, if SOCKET_ID_ANY was specified as a
     * socket ID argument, we must only look at native memory and ignore any
     * page sizes associated with external memory.
     */
    valid = msl->socket_id == wa->socket_id;
    valid |= wa->socket_id == SOCKET_ID_ANY && msl->external == 0;

    if (valid && msl->page_sz < wa->min)
        wa->min = msl->page_sz;

    return 0;
}

static size_t
get_min_page_size(int socket_id) {
    struct pagesz_walk_arg wa;

    wa.min = SIZE_MAX;
    wa.socket_id = socket_id;

    rte_memseg_list_walk(find_min_pagesz, &wa);

    return wa.min == SIZE_MAX ? (size_t) rte_mem_page_size() : wa.min;
}


static void
mempool_add_elem(struct rte_mempool *mp, __rte_unused void *opaque,
                 void *obj, rte_iova_t iova) {
    struct rte_mempool_objhdr *hdr;
    struct rte_mempool_objtlr *tlr
    __rte_unused;

    /* set mempool ptr in header */
    hdr = RTE_PTR_SUB(obj, sizeof(*hdr));
    hdr->mp = mp;
    hdr->iova = iova;
    STAILQ_INSERT_TAIL(&mp->elt_list, hdr, next);
    mp->populated_size++;

#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE2;
    tlr = __mempool_get_trailer(obj);
    tlr->cookie = RTE_MEMPOOL_TRAILER_COOKIE;
#endif
}

/* call obj_cb() for each mempool element */
uint32_t
rte_mempool_obj_iter(struct rte_mempool *mp,
                     rte_mempool_obj_cb_t *obj_cb, void *obj_cb_arg) {
    struct rte_mempool_objhdr *hdr;
    void *obj;
    unsigned n = 0;

    STAILQ_FOREACH(hdr, &mp->elt_list, next)
    {
        obj = (char *) hdr + sizeof(*hdr);
        obj_cb(mp, obj_cb_arg, obj, n);
        n++;
    }

    return n;
}

/* call mem_cb() for each mempool memory chunk */
uint32_t
rte_mempool_mem_iter(struct rte_mempool *mp,
                     rte_mempool_mem_cb_t *mem_cb, void *mem_cb_arg) {
    struct rte_mempool_memhdr *hdr;
    unsigned n = 0;

    STAILQ_FOREACH(hdr, &mp->mem_list, next)
    {
        mem_cb(mp, mem_cb_arg, hdr, n);
        n++;
    }

    return n;
}

/* get the header, trailer and total size of a mempool element. */
uint32_t
rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags,
                          struct rte_mempool_objsz *sz) {
    //如果传过来的sz为空则使用本地的对象，否则使用传过来的sz
    struct rte_mempool_objsz lsz;
    sz = (sz != NULL) ? sz : &lsz;
    //设置每个对象的头大小
    sz->header_size = sizeof(struct rte_mempool_objhdr);
    if ((flags & MEMPOOL_F_NO_CACHE_ALIGN) == 0)
        sz->header_size = RTE_ALIGN_CEIL(sz->header_size,
                                         RTE_MEMPOOL_ALIGN);

#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    //当debug模式开启时，尾部大小为sizeof(struct rte_mempool_objtlr)
    sz->trailer_size = sizeof(struct rte_mempool_objtlr);
#else
    //当debug模式未开启，不需要struct rte_mempool_objtlr空间
    sz->trailer_size = 0;
#endif

    /* element size is 8 bytes-aligned at least */
    //元素大小最小为8字节对齐
    sz->elt_size = RTE_ALIGN_CEIL(elt_size, sizeof(uint64_t));

    /* expand trailer to next cache line */
    if ((flags & MEMPOOL_F_NO_CACHE_ALIGN) == 0) {
        sz->total_size = sz->header_size + sz->elt_size +
                         sz->trailer_size;
        sz->trailer_size += ((RTE_MEMPOOL_ALIGN -
                              (sz->total_size & RTE_MEMPOOL_ALIGN_MASK)) &
                             RTE_MEMPOOL_ALIGN_MASK);
    }

    /*
     * increase trailer to add padding between objects in order to
     * spread them across memory channels/ranks
     */
    if ((flags & MEMPOOL_F_NO_SPREAD) == 0) {
        unsigned new_size;
        new_size = arch_mem_object_align
                (sz->header_size + sz->elt_size + sz->trailer_size);
        sz->trailer_size = new_size - sz->header_size - sz->elt_size;
    }

    /* this is the size of an object, including header and trailer */
    //计算最后的每个对象的总长度
    sz->total_size = sz->header_size + sz->elt_size + sz->trailer_size;

    return sz->total_size;
}

/* free a memchunk allocated with rte_memzone_reserve() */
static void
rte_mempool_memchunk_mz_free(__rte_unused struct rte_mempool_memhdr *memhdr,
                             void *opaque) {
    const struct rte_memzone *mz = opaque;
    rte_memzone_free(mz);
}

/* Free memory chunks used by a mempool. Objects must be in pool */
static void
rte_mempool_free_memchunks(struct rte_mempool *mp) {
    struct rte_mempool_memhdr *memhdr;
    void *elt;

    while (!STAILQ_EMPTY(&mp->elt_list)) {
        rte_mempool_ops_dequeue_bulk(mp, &elt, 1);
        (void) elt;
        STAILQ_REMOVE_HEAD(&mp->elt_list, next);
        mp->populated_size--;
    }

    while (!STAILQ_EMPTY(&mp->mem_list)) {
        memhdr = STAILQ_FIRST(&mp->mem_list);
        STAILQ_REMOVE_HEAD(&mp->mem_list, next);
        if (memhdr->free_cb != NULL)
            memhdr->free_cb(memhdr, memhdr->opaque);
        rte_free(memhdr);
        mp->nb_mem_chunks--;
    }
}

static int
mempool_ops_alloc_once(struct rte_mempool *mp) {
    int ret;

    /* create the internal ring if not already done */
    if ((mp->flags & MEMPOOL_F_POOL_CREATED) == 0) {
        ret = rte_mempool_ops_alloc(mp);
        if (ret != 0)
            return ret;
        mp->flags |= MEMPOOL_F_POOL_CREATED;
    }
    return 0;
}

/* Add objects in the pool, using a physically contiguous memory
 * zone. Return the number of objects added, or a negative value
 * on error.
 */
int
rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
                          rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
                          void *opaque) {
    unsigned i = 0;
    size_t off;
    struct rte_mempool_memhdr *memhdr;
    int ret;

    ret = mempool_ops_alloc_once(mp);
    if (ret != 0)
        return ret;

    /* mempool is already populated */
    if (mp->populated_size >= mp->size)
        return -ENOSPC;

    memhdr = rte_zmalloc("MEMPOOL_MEMHDR", sizeof(*memhdr), 0);
    if (memhdr == NULL)
        return -ENOMEM;

    memhdr->mp = mp;
    memhdr->addr = vaddr;
    memhdr->iova = iova;
    memhdr->len = len;
    memhdr->free_cb = free_cb;
    memhdr->opaque = opaque;

    if (mp->flags & MEMPOOL_F_NO_CACHE_ALIGN)
        off = RTE_PTR_ALIGN_CEIL(vaddr, 8) - vaddr;
    else
        off = RTE_PTR_ALIGN_CEIL(vaddr, RTE_MEMPOOL_ALIGN) - vaddr;

    if (off > len) {
        ret = 0;
        goto fail;
    }

    i = rte_mempool_ops_populate(mp, mp->size - mp->populated_size,
                                 (char *) vaddr + off,
                                 (iova == RTE_BAD_IOVA) ? RTE_BAD_IOVA : (iova + off),
                                 len - off, mempool_add_elem, NULL);

    /* not enough room to store one object */
    if (i == 0) {
        ret = 0;
        goto fail;
    }

    STAILQ_INSERT_TAIL(&mp->mem_list, memhdr, next);
    mp->nb_mem_chunks++;

    rte_mempool_trace_populate_iova(mp, vaddr, iova, len, free_cb, opaque);
    return i;

    fail:
    rte_free(memhdr);
    return ret;
}

static rte_iova_t
get_iova(void *addr) {
    struct rte_memseg *ms;

    /* try registered memory first */
    ms = rte_mem_virt2memseg(addr, NULL);
    if (ms == NULL || ms->iova == RTE_BAD_IOVA)
        /* fall back to actual physical address */
        return rte_mem_virt2iova(addr);
    return ms->iova + RTE_PTR_DIFF(addr, ms->addr);
}

/* Populate the mempool with a virtual area. Return the number of
 * objects added, or a negative value on error.
 */
int
rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
                          size_t len, size_t pg_sz, rte_mempool_memchunk_free_cb_t *free_cb,
                          void *opaque) {
    rte_iova_t iova;
    size_t off, phys_len;
    int ret, cnt = 0;

    if (mp->flags & MEMPOOL_F_NO_IOVA_CONTIG)
        return rte_mempool_populate_iova(mp, addr, RTE_BAD_IOVA,
                                         len, free_cb, opaque);

    for (off = 0; off < len &&
                  mp->populated_size < mp->size; off += phys_len) {

        iova = get_iova(addr + off);

        /* populate with the largest group of contiguous pages */
        for (phys_len = RTE_MIN(
                (size_t)(RTE_PTR_ALIGN_CEIL(addr + off + 1, pg_sz) -
                         (addr + off)),
                len - off);
             off + phys_len < len;
             phys_len = RTE_MIN(phys_len + pg_sz, len - off)) {
            rte_iova_t iova_tmp;

            iova_tmp = get_iova(addr + off + phys_len);

            if (iova_tmp == RTE_BAD_IOVA ||
                iova_tmp != iova + phys_len)
                break;
        }

        ret = rte_mempool_populate_iova(mp, addr + off, iova,
                                        phys_len, free_cb, opaque);
        if (ret == 0)
            continue;
        if (ret < 0)
            goto fail;
        /* no need to call the free callback for next chunks */
        free_cb = NULL;
        cnt += ret;
    }

    rte_mempool_trace_populate_virt(mp, addr, len, pg_sz, free_cb, opaque);
    return cnt;

    fail:
    rte_mempool_free_memchunks(mp);
    return ret;
}

/* Get the minimal page size used in a mempool before populating it. */
int
rte_mempool_get_page_size(struct rte_mempool *mp, size_t *pg_sz) {
    bool need_iova_contig_obj;
    bool alloc_in_ext_mem;
    int ret;

    /* check if we can retrieve a valid socket ID */
    ret = rte_malloc_heap_socket_is_external(mp->socket_id);
    if (ret < 0)
        return -EINVAL;
    alloc_in_ext_mem = (ret == 1);
    need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);

    if (!need_iova_contig_obj)
        *pg_sz = 0;
    else if (rte_eal_has_hugepages() || alloc_in_ext_mem)
        *pg_sz = get_min_page_size(mp->socket_id);
    else
        *pg_sz = rte_mem_page_size();

    rte_mempool_trace_get_page_size(mp, *pg_sz);
    return 0;
}

/* Default function to populate the mempool: allocate memory in memzones,
 * and populate them. Return the number of objects added, or a negative
 * value on error.
 */
int
rte_mempool_populate_default(struct rte_mempool *mp) {
    unsigned int mz_flags = RTE_MEMZONE_1GB | RTE_MEMZONE_SIZE_HINT_ONLY;
    char mz_name[RTE_MEMZONE_NAMESIZE];
    const struct rte_memzone *mz;
    ssize_t mem_size;
    size_t align, pg_sz, pg_shift = 0;
    rte_iova_t iova;
    unsigned mz_id, n;
    int ret;
    bool need_iova_contig_obj;
    size_t max_alloc_size = SIZE_MAX;

    ret = mempool_ops_alloc_once(mp);
    if (ret != 0)
        return ret;

    /* mempool must not be populated */
    if (mp->nb_mem_chunks != 0)
        return -EEXIST;

    /*
     * the following section calculates page shift and page size values.
     *
     * these values impact the result of calc_mem_size operation, which
     * returns the amount of memory that should be allocated to store the
     * desired number of objects. when not zero, it allocates more memory
     * for the padding between objects, to ensure that an object does not
     * cross a page boundary. in other words, page size/shift are to be set
     * to zero if mempool elements won't care about page boundaries.
     * there are several considerations for page size and page shift here.
     *
     * if we don't need our mempools to have physically contiguous objects,
     * then just set page shift and page size to 0, because the user has
     * indicated that there's no need to care about anything.
     *
     * if we do need contiguous objects (if a mempool driver has its
     * own calc_size() method returning min_chunk_size = mem_size),
     * there is also an option to reserve the entire mempool memory
     * as one contiguous block of memory.
     *
     * if we require contiguous objects, but not necessarily the entire
     * mempool reserved space to be contiguous, pg_sz will be != 0,
     * and the default ops->populate() will take care of not placing
     * objects across pages.
     *
     * if our IO addresses are physical, we may get memory from bigger
     * pages, or we might get memory from smaller pages, and how much of it
     * we require depends on whether we want bigger or smaller pages.
     * However, requesting each and every memory size is too much work, so
     * what we'll do instead is walk through the page sizes available, pick
     * the smallest one and set up page shift to match that one. We will be
     * wasting some space this way, but it's much nicer than looping around
     * trying to reserve each and every page size.
     *
     * If we fail to get enough contiguous memory, then we'll go and
     * reserve space in smaller chunks.
     */

    need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);
    ret = rte_mempool_get_page_size(mp, &pg_sz);
    if (ret < 0)
        return ret;

    if (pg_sz != 0)
        pg_shift = rte_bsf32(pg_sz);

    for (mz_id = 0, n = mp->size; n > 0; mz_id++, n -= ret) {
        size_t min_chunk_size;

        mem_size = rte_mempool_ops_calc_mem_size(
                mp, n, pg_shift, &min_chunk_size, &align);

        if (mem_size < 0) {
            ret = mem_size;
            goto fail;
        }

        ret = snprintf(mz_name, sizeof(mz_name),
                       RTE_MEMPOOL_MZ_FORMAT "_%d", mp->name, mz_id);
        if (ret < 0 || ret >= (int) sizeof(mz_name)) {
            ret = -ENAMETOOLONG;
            goto fail;
        }

        /* if we're trying to reserve contiguous memory, add appropriate
         * memzone flag.
         */
        if (min_chunk_size == (size_t) mem_size)
            mz_flags |= RTE_MEMZONE_IOVA_CONTIG;

        /* Allocate a memzone, retrying with a smaller area on ENOMEM */
        do {
            mz = rte_memzone_reserve_aligned(mz_name,
                                             RTE_MIN((size_t) mem_size, max_alloc_size),
                                             mp->socket_id, mz_flags, align);

            if (mz != NULL || rte_errno != ENOMEM)
                break;

            max_alloc_size = RTE_MIN(max_alloc_size,
                                     (size_t) mem_size) / 2;
        } while (mz == NULL && max_alloc_size >= min_chunk_size);

        if (mz == NULL) {
            ret = -rte_errno;
            goto fail;
        }

        if (need_iova_contig_obj)
            iova = mz->iova;
        else
            iova = RTE_BAD_IOVA;

        if (pg_sz == 0 || (mz_flags & RTE_MEMZONE_IOVA_CONTIG))
            ret = rte_mempool_populate_iova(mp, mz->addr,
                                            iova, mz->len,
                                            rte_mempool_memchunk_mz_free,
                                            (void *) (uintptr_t) mz);
        else
            ret = rte_mempool_populate_virt(mp, mz->addr,
                                            mz->len, pg_sz,
                                            rte_mempool_memchunk_mz_free,
                                            (void *) (uintptr_t) mz);
        if (ret == 0) /* should not happen */
            ret = -ENOBUFS;
        if (ret < 0) {
            rte_memzone_free(mz);
            goto fail;
        }
    }

    rte_mempool_trace_populate_default(mp);
    return mp->size;

    fail:
    rte_mempool_free_memchunks(mp);
    return ret;
}

/* return the memory size required for mempool objects in anonymous mem */
static ssize_t
get_anon_size(const struct rte_mempool *mp) {
    ssize_t size;
    size_t pg_sz, pg_shift;
    size_t min_chunk_size;
    size_t align;

    pg_sz = rte_mem_page_size();
    pg_shift = rte_bsf32(pg_sz);
    size = rte_mempool_ops_calc_mem_size(mp, mp->size, pg_shift,
                                         &min_chunk_size, &align);

    return size;
}

/* unmap a memory zone mapped by rte_mempool_populate_anon() */
static void
rte_mempool_memchunk_anon_free(struct rte_mempool_memhdr *memhdr,
                               void *opaque) {
    ssize_t size;

    /*
     * Calculate size since memhdr->len has contiguous chunk length
     * which may be smaller if anon map is split into many contiguous
     * chunks. Result must be the same as we calculated on populate.
     */
    size = get_anon_size(memhdr->mp);
    if (size < 0)
        return;

    rte_mem_unmap(opaque, size);
}

/* populate the mempool with an anonymous mapping */
int
rte_mempool_populate_anon(struct rte_mempool *mp) {
    ssize_t size;
    int ret;
    char *addr;

    /* mempool is already populated, error */
    if ((!STAILQ_EMPTY(&mp->mem_list)) || mp->nb_mem_chunks != 0) {
        rte_errno = EINVAL;
        return 0;
    }

    ret = mempool_ops_alloc_once(mp);
    if (ret < 0) {
        rte_errno = -ret;
        return 0;
    }

    size = get_anon_size(mp);
    if (size < 0) {
        rte_errno = -size;
        return 0;
    }

    /* get chunk of virtually continuous memory */
    addr = rte_mem_map(NULL, size, RTE_PROT_READ | RTE_PROT_WRITE,
                       RTE_MAP_SHARED | RTE_MAP_ANONYMOUS, -1, 0);
    if (addr == NULL)
        return 0;
    /* can't use MMAP_LOCKED, it does not exist on BSD */
    if (rte_mem_lock(addr, size) < 0) {
        rte_mem_unmap(addr, size);
        return 0;
    }

    ret = rte_mempool_populate_virt(mp, addr, size, rte_mem_page_size(),
                                    rte_mempool_memchunk_anon_free, addr);
    if (ret == 0) /* should not happen */
        ret = -ENOBUFS;
    if (ret < 0) {
        rte_errno = -ret;
        goto fail;
    }

    rte_mempool_trace_populate_anon(mp);
    return mp->populated_size;

    fail:
    rte_mempool_free_memchunks(mp);
    return 0;
}

/* free a mempool */
void
rte_mempool_free(struct rte_mempool *mp) {
    struct rte_mempool_list *mempool_list = NULL;
    struct rte_tailq_entry *te;

    if (mp == NULL)
        return;

    mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);
    rte_mcfg_tailq_write_lock();
    /* find out tailq entry */
    TAILQ_FOREACH(te, mempool_list, next)
    {
        if (te->data == (void *) mp)
            break;
    }

    if (te != NULL) {
        TAILQ_REMOVE(mempool_list, te, next);
        rte_free(te);
    }
    rte_mcfg_tailq_write_unlock();

    rte_mempool_trace_free(mp);
    rte_mempool_free_memchunks(mp);
    rte_mempool_ops_free(mp);
    rte_memzone_free(mp->mz);
}

static void
mempool_cache_init(struct rte_mempool_cache *cache, uint32_t size) {
    cache->size = size;
    cache->flushthresh = CALC_CACHE_FLUSHTHRESH(size);
    cache->len = 0;
}

/*
 * Create and initialize a cache for objects that are retrieved from and
 * returned to an underlying mempool. This structure is identical to the
 * local_cache[lcore_id] pointed to by the mempool structure.
 */
struct rte_mempool_cache *
rte_mempool_cache_create(uint32_t size, int socket_id) {
    struct rte_mempool_cache *cache;

    if (size == 0 || size > RTE_MEMPOOL_CACHE_MAX_SIZE) {
        rte_errno = EINVAL;
        return NULL;
    }

    cache = rte_zmalloc_socket("MEMPOOL_CACHE", sizeof(*cache),
                               RTE_CACHE_LINE_SIZE, socket_id);
    if (cache == NULL) {
        RTE_LOG(ERR, MEMPOOL, "Cannot allocate mempool cache.\n");
        rte_errno = ENOMEM;
        return NULL;
    }

    mempool_cache_init(cache, size);

    rte_mempool_trace_cache_create(size, socket_id, cache);
    return cache;
}

/*
 * Free a cache. It's the responsibility of the user to make sure that any
 * remaining objects in the cache are flushed to the corresponding
 * mempool.
 */
void
rte_mempool_cache_free(struct rte_mempool_cache *cache) {
    rte_mempool_trace_cache_free(cache);
    rte_free(cache);
}

/* create an empty mempool */
struct rte_mempool *
rte_mempool_create_empty(const char *name, unsigned n, unsigned elt_size,
                         unsigned cache_size, unsigned private_data_size,
                         int socket_id, unsigned flags) {
    //内存区域的名称
    char mz_name[RTE_MEMZONE_NAMESIZE];
    struct rte_mempool_list *mempool_list;
    struct rte_mempool *mp = NULL;
    struct rte_tailq_entry *te = NULL;
    const struct rte_memzone *mz = NULL;
    size_t mempool_size;
    unsigned int mz_flags = RTE_MEMZONE_1GB | RTE_MEMZONE_SIZE_HINT_ONLY;
    struct rte_mempool_objsz objsz;
    unsigned lcore_id;
    int ret;

    /* compilation-time checks */
    // 判断struct rte_mempool是否与缓存线对齐
    RTE_BUILD_BUG_ON((sizeof(struct rte_mempool) &
                      RTE_CACHE_LINE_MASK) != 0);
    // 判断struct rte_mempool_cache是否与缓存线对齐
    RTE_BUILD_BUG_ON((sizeof(struct rte_mempool_cache) &
                      RTE_CACHE_LINE_MASK) != 0);
#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    RTE_BUILD_BUG_ON((sizeof(struct rte_mempool_debug_stats) &
              RTE_CACHE_LINE_MASK) != 0);
    RTE_BUILD_BUG_ON((offsetof(struct rte_mempool, stats) &
              RTE_CACHE_LINE_MASK) != 0);
#endif

    //获取共享内存的内存池队列
    mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);

    /* asked for zero items */
    if (n == 0) {
        //创建元素个数为0，报错
        rte_errno = EINVAL;
        return NULL;
    }

    /* asked cache too big */
    if (cache_size > RTE_MEMPOOL_CACHE_MAX_SIZE ||
        CALC_CACHE_FLUSHTHRESH(cache_size) > n) {
        // 判断缓存大小是否超过最大大小以及是否大于 n / 1.5
        // 如果超过，报错
        rte_errno = EINVAL;
        return NULL;
    }

    /* "no cache align" imply "no spread" */
    if (flags & MEMPOOL_F_NO_CACHE_ALIGN)
        //如果用户指定了 MEMPOOL_F_NO_CACHE_ALIGN 则 MEMPOOL_F_NO_SPREAD 也要指定
        flags |= MEMPOOL_F_NO_SPREAD;

    /* calculate mempool object sizes. */
    //计算内存池对象的大小
    if (!rte_mempool_calc_obj_size(elt_size, flags, &objsz)) {
        rte_errno = EINVAL;
        return NULL;
    }

    //加锁
    rte_mcfg_mempool_write_lock();

    /*
     * reserve a memory zone for this mempool: private data is
     * cache-aligned
     * 为内存池预留一个内存区域：缓存对齐的私有数据空间
     */
    private_data_size = (private_data_size +
                         RTE_MEMPOOL_ALIGN_MASK) & (~RTE_MEMPOOL_ALIGN_MASK);


    /* try to allocate tailq entry */
    //分配空间给rte_tailq_entry
    te = rte_zmalloc("MEMPOOL_TAILQ_ENTRY", sizeof(*te), 0);
    if (te == NULL) {
        RTE_LOG(ERR, MEMPOOL, "Cannot allocate tailq entry!\n");
        goto exit_unlock;
    }

    //设置缓存的空间大小
    mempool_size = MEMPOOL_HEADER_SIZE(mp, cache_size);
    //设置私有数据空间大小
    mempool_size += private_data_size;
    //设置大小缓存对齐
    mempool_size = RTE_ALIGN_CEIL(mempool_size, RTE_MEMPOOL_ALIGN);

    //设置名称
    ret = snprintf(mz_name, sizeof(mz_name), RTE_MEMPOOL_MZ_FORMAT, name);
    if (ret < 0 || ret >= (int) sizeof(mz_name)) {
        rte_errno = ENAMETOOLONG;
        goto exit_unlock;
    }

    //分配内存池空间
    mz = rte_memzone_reserve(mz_name, mempool_size, socket_id, mz_flags);
    if (mz == NULL)
        goto exit_unlock;

    /* init the mempool structure */
    //初始化内存池结构体相关参数
    //内存池地址
    mp = mz->addr;
    //内存池头全部置为0
    memset(mp, 0, MEMPOOL_HEADER_SIZE(mp, cache_size));
    //设置内存池名字
    ret = strlcpy(mp->name, name, sizeof(mp->name));
    if (ret < 0 || ret >= (int) sizeof(mp->name)) {
        rte_errno = ENAMETOOLONG;
        goto exit_unlock;
    }
    //设置内存区域对象指针
    mp->mz = mz;
    //设置对象元素个数
    mp->size = n;
    //设置标记
    mp->flags = flags;
    //设置socket_id
    mp->socket_id = socket_id;
    //设置每个元素的大小
    mp->elt_size = objsz.elt_size;
    //设置每个元素的头大小
    mp->header_size = objsz.header_size;
    //设置每个元素的尾部大小
    mp->trailer_size = objsz.trailer_size;
    /* Size of default caches, zero means disabled. */
    //设置缓存的大小，为0的表示没有开启缓存
    mp->cache_size = cache_size;
    //私有数据区域大小
    mp->private_data_size = private_data_size;
    //初始化元素队列
    STAILQ_INIT(&mp->elt_list);
    //初始化内存块队列
    STAILQ_INIT(&mp->mem_list);

    /*
     * local_cache pointer is set even if cache_size is zero.
     * The local_cache points to just past the elt_pa[] array.
     * 设置本地缓存，即使缓存大小设置为0，也会初始化缓存
     */
    mp->local_cache = (struct rte_mempool_cache *)
            RTE_PTR_ADD(mp, MEMPOOL_HEADER_SIZE(mp, 0));

    /* Init all default caches. */
    if (cache_size != 0) {
        //如果缓存大小不为0，则遍历初始化所有的核缓存
        for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++)
            mempool_cache_init(&mp->local_cache[lcore_id],
                               cache_size);
    }
    //设置队列节点数据区域为该内存池
    te->data = mp;

    //将该队列节点加入到队列中
    rte_mcfg_tailq_write_lock();
    TAILQ_INSERT_TAIL(mempool_list, te, next);
    rte_mcfg_tailq_write_unlock();
    rte_mcfg_mempool_write_unlock();

    rte_mempool_trace_create_empty(name, n, elt_size, cache_size,
                                   private_data_size, flags, mp);
    return mp;

    exit_unlock:
    rte_mcfg_mempool_write_unlock();
    rte_free(te);
    rte_mempool_free(mp);
    return NULL;
}

/* create the mempool */
struct rte_mempool *
rte_mempool_create(const char *name, unsigned n, unsigned elt_size,
                   unsigned cache_size, unsigned private_data_size,
                   rte_mempool_ctor_t *mp_init, void *mp_init_arg,
                   rte_mempool_obj_cb_t *obj_init, void *obj_init_arg,
                   int socket_id, unsigned flags) {
    int ret;
    struct rte_mempool *mp;

    //创建一个空的内存池
    mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
                                  private_data_size, socket_id, flags);
    if (mp == NULL)
        //创建错误，返回NULL
        return NULL;

    /*
     * Since we have 4 combinations of the SP/SC/MP/MC examine the flags to
     * set the correct index into the table of ops structs.
     *
     * 有SP/SC/MP/MC 4种组合，检查这些标志，以将正确的索引设置到ops结构表中。
     *
     */
    if ((flags & MEMPOOL_F_SP_PUT) && (flags & MEMPOOL_F_SC_GET))
        //单个生产者与单个消费者模式
        ret = rte_mempool_set_ops_byname(mp, "ring_sp_sc", NULL);
    else if (flags & MEMPOOL_F_SP_PUT)
        //单个生产者与多个消费者模式
        ret = rte_mempool_set_ops_byname(mp, "ring_sp_mc", NULL);
    else if (flags & MEMPOOL_F_SC_GET)
        //多个生产者与单个消费者模式
        ret = rte_mempool_set_ops_byname(mp, "ring_mp_sc", NULL);
    else
        //多个生产者与多个消费者模式
        ret = rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);

    if (ret)
        //设置模式标记失败，跳转错误代码段
        goto fail;

    /* call the mempool priv initializer */
    //内存池初始化完毕，调用init回调方法
    if (mp_init)
        mp_init(mp, mp_init_arg);

    //填充默认值
    if (rte_mempool_populate_default(mp) < 0)
        goto fail;

    /* call the object initializers */
    //当obj_init回调函数存在时，遍历对象并调用回调函数
    if (obj_init)
        rte_mempool_obj_iter(mp, obj_init, obj_init_arg);

    rte_mempool_trace_create(name, n, elt_size, cache_size,
                             private_data_size, mp_init, mp_init_arg, obj_init,
                             obj_init_arg, flags, mp);
    return mp;

    fail:
    //执行错误，释放资源
    rte_mempool_free(mp);
    return NULL;
}

/* Return the number of entries in the mempool */
unsigned int
rte_mempool_avail_count(const struct rte_mempool *mp) {
    unsigned count;
    unsigned lcore_id;

    count = rte_mempool_ops_get_count(mp);

    if (mp->cache_size == 0)
        return count;

    for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++)
        count += mp->local_cache[lcore_id].len;

    /*
     * due to race condition (access to len is not locked), the
     * total can be greater than size... so fix the result
     */
    if (count > mp->size)
        return mp->size;
    return count;
}

/* return the number of entries allocated from the mempool */
unsigned int
rte_mempool_in_use_count(const struct rte_mempool *mp) {
    return mp->size - rte_mempool_avail_count(mp);
}

/* dump the cache status */
static unsigned
rte_mempool_dump_cache(FILE *f, const struct rte_mempool *mp) {
    unsigned lcore_id;
    unsigned count = 0;
    unsigned cache_count;

    fprintf(f, "  internal cache infos:\n");
    fprintf(f, "    cache_size=%"
    PRIu32
    "\n", mp->cache_size);

    if (mp->cache_size == 0)
        return count;

    for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
        cache_count = mp->local_cache[lcore_id].len;
        fprintf(f, "    cache_count[%u]=%"
        PRIu32
        "\n",
                lcore_id, cache_count);
        count += cache_count;
    }
    fprintf(f, "    total_cache_count=%u\n", count);
    return count;
}

#ifndef __INTEL_COMPILER
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif

/* check and update cookies or panic (internal) */
void rte_mempool_check_cookies(const struct rte_mempool *mp,
                               void *const *obj_table_const, unsigned n, int free) {
#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    struct rte_mempool_objhdr *hdr;
    struct rte_mempool_objtlr *tlr;
    uint64_t cookie;
    void *tmp;
    void *obj;
    void **obj_table;

    /* Force to drop the "const" attribute. This is done only when
     * DEBUG is enabled */
    tmp = (void *) obj_table_const;
    obj_table = tmp;

    while (n--) {
        obj = obj_table[n];

        if (rte_mempool_from_obj(obj) != mp)
            rte_panic("MEMPOOL: object is owned by another "
                  "mempool\n");

        hdr = __mempool_get_header(obj);
        cookie = hdr->cookie;

        if (free == 0) {
            if (cookie != RTE_MEMPOOL_HEADER_COOKIE1) {
                RTE_LOG(CRIT, MEMPOOL,
                    "obj=%p, mempool=%p, cookie=%" PRIx64 "\n",
                    obj, (const void *) mp, cookie);
                rte_panic("MEMPOOL: bad header cookie (put)\n");
            }
            hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE2;
        } else if (free == 1) {
            if (cookie != RTE_MEMPOOL_HEADER_COOKIE2) {
                RTE_LOG(CRIT, MEMPOOL,
                    "obj=%p, mempool=%p, cookie=%" PRIx64 "\n",
                    obj, (const void *) mp, cookie);
                rte_panic("MEMPOOL: bad header cookie (get)\n");
            }
            hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE1;
        } else if (free == 2) {
            if (cookie != RTE_MEMPOOL_HEADER_COOKIE1 &&
                cookie != RTE_MEMPOOL_HEADER_COOKIE2) {
                RTE_LOG(CRIT, MEMPOOL,
                    "obj=%p, mempool=%p, cookie=%" PRIx64 "\n",
                    obj, (const void *) mp, cookie);
                rte_panic("MEMPOOL: bad header cookie (audit)\n");
            }
        }
        tlr = __mempool_get_trailer(obj);
        cookie = tlr->cookie;
        if (cookie != RTE_MEMPOOL_TRAILER_COOKIE) {
            RTE_LOG(CRIT, MEMPOOL,
                "obj=%p, mempool=%p, cookie=%" PRIx64 "\n",
                obj, (const void *) mp, cookie);
            rte_panic("MEMPOOL: bad trailer cookie\n");
        }
    }
#else
    RTE_SET_USED(mp);
    RTE_SET_USED(obj_table_const);
    RTE_SET_USED(n);
    RTE_SET_USED(free);
#endif
}

void
rte_mempool_contig_blocks_check_cookies(const struct rte_mempool *mp,
                                        void *const *first_obj_table_const, unsigned int n, int free) {
#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    struct rte_mempool_info info;
    const size_t total_elt_sz =
        mp->header_size + mp->elt_size + mp->trailer_size;
    unsigned int i, j;

    rte_mempool_ops_get_info(mp, &info);

    for (i = 0; i < n; ++i) {
        void *first_obj = first_obj_table_const[i];

        for (j = 0; j < info.contig_block_size; ++j) {
            void *obj;

            obj = (void *)((uintptr_t)first_obj + j * total_elt_sz);
            rte_mempool_check_cookies(mp, &obj, 1, free);
        }
    }
#else
    RTE_SET_USED(mp);
    RTE_SET_USED(first_obj_table_const);
    RTE_SET_USED(n);
    RTE_SET_USED(free);
#endif
}

#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
static void
mempool_obj_audit(struct rte_mempool *mp, __rte_unused void *opaque,
    void *obj, __rte_unused unsigned idx)
{
    __mempool_check_cookies(mp, &obj, 1, 2);
}

static void
mempool_audit_cookies(struct rte_mempool *mp)
{
    unsigned num;

    num = rte_mempool_obj_iter(mp, mempool_obj_audit, NULL);
    if (num != mp->size) {
        rte_panic("rte_mempool_obj_iter(mempool=%p, size=%u) "
            "iterated only over %u elements\n",
            mp, mp->size, num);
    }
}
#else
#define mempool_audit_cookies(mp) do {} while(0)
#endif

#ifndef __INTEL_COMPILER
#pragma GCC diagnostic error "-Wcast-qual"
#endif

/* check cookies before and after objects */
static void
mempool_audit_cache(const struct rte_mempool *mp) {
    /* check cache size consistency */
    unsigned lcore_id;

    if (mp->cache_size == 0)
        return;

    for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
        const struct rte_mempool_cache *cache;
        cache = &mp->local_cache[lcore_id];
        if (cache->len > RTE_DIM(cache->objs)) {
            RTE_LOG(CRIT, MEMPOOL, "badness on cache[%u]\n",
                    lcore_id);
            rte_panic("MEMPOOL: invalid cache len\n");
        }
    }
}

/* check the consistency of mempool (size, cookies, ...) */
void
rte_mempool_audit(struct rte_mempool *mp) {
    mempool_audit_cache(mp);
    mempool_audit_cookies(mp);

    /* For case where mempool DEBUG is not set, and cache size is 0 */
    RTE_SET_USED(mp);
}

/* dump the status of the mempool on the console */
void
rte_mempool_dump(FILE *f, struct rte_mempool *mp) {
#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    struct rte_mempool_info info;
    struct rte_mempool_debug_stats sum;
    unsigned lcore_id;
#endif
    struct rte_mempool_memhdr *memhdr;
    struct rte_mempool_ops *ops;
    unsigned common_count;
    unsigned cache_count;
    size_t mem_len = 0;

    RTE_ASSERT(f != NULL);
    RTE_ASSERT(mp != NULL);

    fprintf(f, "mempool <%s>@%p\n", mp->name, mp);
    fprintf(f, "  flags=%x\n", mp->flags);
    fprintf(f, "  socket_id=%d\n", mp->socket_id);
    fprintf(f, "  pool=%p\n", mp->pool_data);
    fprintf(f, "  iova=0x%"
    PRIx64
    "\n", mp->mz->iova);
    fprintf(f, "  nb_mem_chunks=%u\n", mp->nb_mem_chunks);
    fprintf(f, "  size=%"
    PRIu32
    "\n", mp->size);
    fprintf(f, "  populated_size=%"
    PRIu32
    "\n", mp->populated_size);
    fprintf(f, "  header_size=%"
    PRIu32
    "\n", mp->header_size);
    fprintf(f, "  elt_size=%"
    PRIu32
    "\n", mp->elt_size);
    fprintf(f, "  trailer_size=%"
    PRIu32
    "\n", mp->trailer_size);
    fprintf(f, "  total_obj_size=%"
    PRIu32
    "\n",
            mp->header_size + mp->elt_size + mp->trailer_size);

    fprintf(f, "  private_data_size=%"
    PRIu32
    "\n", mp->private_data_size);

    fprintf(f, "  ops_index=%d\n", mp->ops_index);
    ops = rte_mempool_get_ops(mp->ops_index);
    fprintf(f, "  ops_name: <%s>\n", (ops != NULL) ? ops->name : "NA");

    STAILQ_FOREACH(memhdr, &mp->mem_list, next)
    mem_len += memhdr->len;
    if (mem_len != 0) {
        fprintf(f, "  avg bytes/object=%#Lf\n",
                (long double) mem_len / mp->size);
    }

    cache_count = rte_mempool_dump_cache(f, mp);
    common_count = rte_mempool_ops_get_count(mp);
    if ((cache_count + common_count) > mp->size)
        common_count = mp->size - cache_count;
    fprintf(f, "  common_pool_count=%u\n", common_count);

    /* sum and dump statistics */
#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
    rte_mempool_ops_get_info(mp, &info);
    memset(&sum, 0, sizeof(sum));
    for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
        sum.put_bulk += mp->stats[lcore_id].put_bulk;
        sum.put_objs += mp->stats[lcore_id].put_objs;
        sum.get_success_bulk += mp->stats[lcore_id].get_success_bulk;
        sum.get_success_objs += mp->stats[lcore_id].get_success_objs;
        sum.get_fail_bulk += mp->stats[lcore_id].get_fail_bulk;
        sum.get_fail_objs += mp->stats[lcore_id].get_fail_objs;
        sum.get_success_blks += mp->stats[lcore_id].get_success_blks;
        sum.get_fail_blks += mp->stats[lcore_id].get_fail_blks;
    }
    fprintf(f, "  stats:\n");
    fprintf(f, "    put_bulk=%"PRIu64"\n", sum.put_bulk);
    fprintf(f, "    put_objs=%"PRIu64"\n", sum.put_objs);
    fprintf(f, "    get_success_bulk=%"PRIu64"\n", sum.get_success_bulk);
    fprintf(f, "    get_success_objs=%"PRIu64"\n", sum.get_success_objs);
    fprintf(f, "    get_fail_bulk=%"PRIu64"\n", sum.get_fail_bulk);
    fprintf(f, "    get_fail_objs=%"PRIu64"\n", sum.get_fail_objs);
    if (info.contig_block_size > 0) {
        fprintf(f, "    get_success_blks=%"PRIu64"\n",
            sum.get_success_blks);
        fprintf(f, "    get_fail_blks=%"PRIu64"\n", sum.get_fail_blks);
    }
#else
    fprintf(f, "  no statistics available\n");
#endif

    rte_mempool_audit(mp);
}

/* dump the status of all mempools on the console */
void
rte_mempool_list_dump(FILE *f) {
    struct rte_mempool *mp = NULL;
    struct rte_tailq_entry *te;
    struct rte_mempool_list *mempool_list;

    mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);

    rte_mcfg_mempool_read_lock();

    TAILQ_FOREACH(te, mempool_list, next)
    {
        mp = (struct rte_mempool *) te->data;
        rte_mempool_dump(f, mp);
    }

    rte_mcfg_mempool_read_unlock();
}

/* search a mempool from its name */
struct rte_mempool *
rte_mempool_lookup(const char *name) {
    struct rte_mempool *mp = NULL;
    struct rte_tailq_entry *te;
    struct rte_mempool_list *mempool_list;

    mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);

    rte_mcfg_mempool_read_lock();

    TAILQ_FOREACH(te, mempool_list, next)
    {
        mp = (struct rte_mempool *) te->data;
        if (strncmp(name, mp->name, RTE_MEMPOOL_NAMESIZE) == 0)
            break;
    }

    rte_mcfg_mempool_read_unlock();

    if (te == NULL) {
        rte_errno = ENOENT;
        return NULL;
    }

    return mp;
}

void rte_mempool_walk(void (*func)(struct rte_mempool *, void *),
                      void *arg) {
    struct rte_tailq_entry *te = NULL;
    struct rte_mempool_list *mempool_list;
    void *tmp_te;

    mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);

    rte_mcfg_mempool_read_lock();

    TAILQ_FOREACH_SAFE(te, mempool_list, next, tmp_te)
    {
        (*func)((struct rte_mempool *) te->data, arg);
    }

    rte_mcfg_mempool_read_unlock();
}
